The invention relates to an apparatus for detecting tape running in a tape recorder, and more particularly to such apparatus in which the running of a tape in a tape recorder is monitored, and when the running of the tape has reached a terminal end thereof, the termination of the magnetic tape being recorded or reproduced is signified to a user by an audible alarm or visual display. Conventional tape recorders are provided with various kinds of devices which are designed to detect the running of the magnetic tape and to signify to a user when a tape being recorded or reproduced has reached a terminal end thereof. In one example, a terminal end of the tape is applied with an electrically conductive foil, which is detected to operate an alarm buzzer. In another example, the tension in the tape is utilized to detect that the terminal end of the tape is reached to thereby operate a mechanical stop mechanism for automatically interrupting a tape drive motor.
However, these proposed devices are complex in arrangement in that the conductive foil is applied to the terminal end of the tape or the mechanical stop mechanism is assembled into the recorder. In addition, these devices occupy a substantial proportion of available space within the recorder, which renders them inadequate for use in a miniature tape recorder using a micro tape cassette. As is well recognized, a tape recorder using a micro tape cassette is greatly reduced in size, preventing the mechanical stop mechanism from being assembled into the recorder. Also the micro tape cassette has a size comparable to that of a small pack of matches, so that it is difficult to apply a further processing to the tape contained therein. However, it is highly desirable that some means for warning of the arrival of terminal end of the tape to a user be provided in the tape recorder using the micro tape cassette, since otherwise the user may be left unnoticed of the lack of available length of the tape, resulting in an irreparable loss of significant information.
On the other hand, in a tape recorder using a storage battery as a drive source, it is necessary to check whether the battery maintains a reference voltage which is required for the normal operation of the recorder, and to indicate the result of the checking operation. If the battery voltage is reduced below the reference voltage, the battery must be replaced for proper operation of the recorder since it is exhausted.
When the magnetic tape is driven for running from the battery supply, it is desirable to provide some means for indicating the tape running. A tape cassette is usually provided with a transparent window through which the tape running can be recognized. However, some tape recorders are constructed such that the window in the tape cassette loaded in position is covered by a covering plate of the recorder, thereby preventing a visual inspection of the running of the internal tape through the window. Therefore, it will be favorable to provide for the recognition of the tape running separately from a visual inspection through the transparent window. However, it is undesirable to provide separate indications of the tape running and battery voltage in view of the space limitation and the economical considerations. Thus, it will be appreciated that the combined indication will be highly desirable.